Led reading light

ABSTRACT

A reading light such as is clipped onto the back of a book has two illuminating color zones; one being yellow/white and the other being blue/white. These are provided by separate LEDs. These LEDs are mounted on one or more arms which can be pivoted from a closed state to a deployed state. A manual switch allows the user to switch between the two different colors of illumination or select both at the same time. This approach enhances user comfort in reading the illuminated material. Certain materials and certain ambient light favor the use of a yellow/light illumination color while other materials and other conditions favor the use of a blue/white illumination color. This provides visual comfort for the user who can select which of the light color ranges is most comfortable and can select both if that provides greater comfort.

BACKGROUND OF THE INVENTION

This invention relates to what is commercially called a book light and more particularly to a book light in which at least two different types of LEDs are employed to provide user selection of different light color zones for illumination.

Book lights are well known and have been used for a long period of time. They are frequently used in situations, such as when reading in bed, where the user desires to direct the illumination onto a page or pages being read without having any significant or annoying amounts of light spread through a wider zone.

The media on which the words are printed and the ink used have an effect on the ease of reading the material involved.

Accordingly, one purpose of this invention is to provide a book light with a light source having a color zone that provides optimum comfort for the reader.

It is a further purpose of this invention to provide a book light device which permits the user to readily select between predetermined color zones.

It is a related purpose of this invention to achieve the above purpose in embodiments which readily clip onto the cover of a book, are light in weight and small in size so that the gain in illumination comfort will not be offset by weight, size or other convenience factors.

BRIEF DESCRIPTION

An illumination device employs two different types of light emitting diodes (LED). The first type of LED provides light having a color in a blue/white light range. The second type of LED has a color in a yellow/white light range. These LEDs on one or more arms may be attached to a mount. The user is provided with a switch which gives the user the option of selecting either the first type of LED or the second type of LED. In one preferred embodiment, the switch has a third position which permits a user to select both types of LEDs at one time.

It has been found that in general, yellow light is more comfortable for augmenting the usual ambient light situation. The yellow light is also more comfortable for most users when reading non-white print stock or print stock containing a large amount of recycled material.

In general, blue light is more comfortable to use at night in a dark room and is also more comfortable to use when reading from bright white print stock with various finishes.

Being able to switch between the two types of LEDs and even being able to select both of them is important to give the user choice and flexibility. What is more comfortable will be a function of the environment and of the individual involved. When reading media in a dark room, the comfort provided by the yellow light or the blue light will very much be a function of the individual involved. Having the individual being able to select whichever is more comfortable makes the reading light more useful and more acceptable.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1 and 2 illustrate respectively a face view and a side view of a preferred embodiment of this invention in a stowed state where the device is not in use.

FIG. 3 shows the FIG. 1 device clipped to the cover of a book with the LED carrying arm 10 rotated approximately 90 degrees about the axis X-X to an intermediate position.

FIG. 4 shows the final use position of the FIG. 1 device in which the LED carrying arm 10 together with an upper portion 16 of the clip carrying arm 16 are twisted 180 degrees about the axis Y-Y of the clip carrying arm. The LED arm plus the upper portion of the clip when twisted 180 degrees serves to position the LEDs 12, 14 over the pages to be read. FIG. 4 also shows the two LED carrying wings 26 in a deployed position to provide enough light to normally cover two open pages of a book.

FIG. 5 is based on a standard industry, chromaticity diagram. The industry standard is in color so that the user can identify zones with color which can be used by the LED manufacturer as the basis for the color of the output of an LED.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 through 4 represent one preferred embodiment. FIGS. 1 and 2 show the device in its closed state. FIG. 4 shows the device in its fully deployed use state. FIG. 3 shows the device in the intermediate state transitioning between the closed state of FIGS. 1 and 2 and the deployed state of FIG. 4.

This embodiment has two arms. The first arm 10 carries sets of LEDs 12 and 14 at one end which will be called herein, the lower portions of the arm. The other arm 16 carries the spring loaded clip 18 which is used to clip the device to the item being read such as the back cover of a book. The LEDs are a first set 12 producing a blue/white light and a second set 14 producing a yellow/white light. A battery (not shown) is included in the clip carrying arm 16.

The compact closed state of the device shown in FIGS. 1 and 2 contrasts with the somewhat expansive deployed state shown in FIG. 4. As may best be seen in FIG. 3, it is desirable to have the clip 18 as the only portion of the device which is on the inside surface of the cover 24C to which it is clipped. To achieve this result, and to provide adequate deployment by the LED sets 12, 14, the two arms 10 are rotatable relative to each other about a common axis X-X at what will be called herein the upper portion of the device. As may best be seen in FIG. 3, the upper portion 20 of the LED carrying arm 10 and the upper portion 22 of the clip carrying arm 16 have a common axis X-X and are rotatable relative to each other about that axis.

When mounting the device to a book 24, the spring loaded clip 18 is inserted over, for example, the back cover of the book so that the clip 18 is inside of the cover 24C and the rest of the device is on the outside of the cover 24C.

To deploy the LEDs 12, 14 so that they illuminate the surface being read, the LED carrying-arm 10 has to be rotated from its position along the outside of the book by about 90 degrees as shown in FIG. 3. This intermediate position shows that the LEDs are facing down on the arm 10 extending away from the book.

What next happens requires the user to twist the upper portion 22 of the arm 20 by 180 degrees (counterclockwise as is shown in FIG. 3) to a point where the LED arm 10 extends forward from the pages of the book. This requires that the top portion 22 of the clip carrying arm 16 be rotatable about an axis Y-Y which is shown in FIG. 1. Thus the top portion 22 of the clip carrying arm 16 can be twisted about the main axis Y-Y of the clip arm 16 to bring the LED carrying arm 10 from the intermediate position shown in FIG. 3 to the use position shown in FIG. 4. The user can then adjust the angle of the LED carrying arm 10 to provide a desired illumination of the pages in the book being read. The line 25 represents the break between the major portion of the arm 16 and the upper portion 22. It is at the break that the upper portion 22 twists about the rest of the arm 16.

In this embodiment, the LEDs 12,14 are carried on two wings 26 which are rotatable on the LED carrying arm 10. These wings 26 are shown in a retracted position in FIG. 3 and in a deployed position in FIG. 4. These wings 26 permit the LEDs 12, 14 to illuminate a greater area. The rotational position of these wings 26 can be adjusted by the user to provide a desired concentration or spreading out of the illumination.

A major reason for the complex rotation of the LED carrying arm 10 (first rotating 90 degrees up from its stored state and then 180 degrees in a twisting motion around the axis Y-Y of the clip carrying arm) is to permit keeping the device on the outside of a book (usually the back cover) when it is not in use so that only the clip is on the inside of the cover and the rest of the device is outside of the cover. Thus it becomes feasible to keep the device clipped to the book being read when the book is put back on the shelf.

LEDs

On each wing 26, there is one LED 12 that provides a blue/white light and a second LED 14 which provides a yellow/white light. A switch 28 is provided so that the user can select either yellow/white illumination or blue/white illumination as the user feels comfortable.

The factors that affect comfort are: (a) ambient light conditions, (b) the reflectivity characteristics of the media being read, (c) the total amount of light (lumens) incident on the media being read, and (d) the personal preferences of the individual using the book light.

Preferably, the switch 28 has a third state in which both sets of LEDs 12 and 14 are turned on. This provides the user with further flexibility so that the user can determine the best lighting arrangement for the comfort of the user in a particular situation.

Generally speaking, the yellow/white LED light is preferable for most people when there is some significant ambient light. Generally speaking the blue/white LED light is preferable when reading in a dark room. In addition, the reflectivity of the media being read will affect which illumination pattern is optimum for the user.

FIG. 5 is a derived from a standard industry chromaticity color diagram. The zone 32 indicates what is designated by a yellow/white terminology herein. The zone 34 illustrates what is designated by a blue/white terminology herein. The yellow/white LEDs of this invention produce light predominantly in the zone 32 and the blue/white LEDs produce light primarily in the zone 34. It should be understood that these are optimum color illumination ranges and that some deviation from the zones 32 and 34 may be within the scope of the invention taught herein. The intensity was that represented by a 7,000 degrees Kelvin temperature. The color zone and the temperature can be varied to suit the environment and preferences of the end user.

Although one preferred embodiment of the invention is disclosed, it should be understood that there are variations on the embodiment that can be made by those skilled in the art encompassed by the invention claimed herein.

For example, a simpler design can be employed in which there are no wings 26 and in which the first set of LEDs 10 would have only a single member and the second set of LEDs 12 would have only a single member. It should be kept in mind herein that the term “set” means a set having as few as one member.

The invention has been described in connection with its use on a book. Yet the invention can be used to illuminate any media to be read including magazines and newspapers.

The value of employing LEDs is in the combination of small size, reasonable cost, ease of selecting the desired color range and long life. It is understood that there are more efficient and perhaps smaller illumination devices being developed. It should be understood that such devices, when made commercially available, shall be equivalent of the LEDs disclosed herein. Accordingly, the term “LEDs” should be understood to include both replacements and improvement which will be developed in the future. 

1. A portable illumination device to facilitate user reading of various media comprising: at least first and second sets of LEDs mounted on the device, said first set of LEDs adapted to project light having a first visible color range, said second set of LEDs adapted to project light having a second visible color range, and a switch coupled to said LEDs and adapted to provide power to said LEDs, said switch having a first on position to turn on only said first set of LEDs and a second on position to turn on only said second set of LEDs.
 2. The illumination device of claim 1 wherein said first color is in a blue/white range and said second color is in a yellow/white range.
 3. The illumination device of claim 1 further comprising: a first arm having a support clip adapted to said first arm to be read, a pivotable arm adjacent to said first arm and pivotal about an axis through said first arm, said first and second sets of LEDs mounted near the upper end of said pivotal arm, said pivotable arm when in a first pivoted position illuminating the item being read and when in a second pivoted position being aligned with said support clip to provide a compact storage state.
 4. The illumination device of claim 3 wherein said first color is in a blue/white range and said second color is in a yellow/white range.
 5. The illumination device of claim 1 wherein: said switch has a third on position to turn on both of said first and second sets of LEDs.
 6. The illumination device of claim 2 wherein: said switch has a third on position to turn on both of said first and second sets of LEDs.
 7. The illumination device of claim 3 wherein: said switch has a third on position to turn on both of said first and second sets of LEDs.
 8. The illumination device of claim 4 wherein: said switch has a third on position to turn on both of said first and second sets of LEDs.
 9. A portable illumination device to facilitate user reading of various media comprising: first and second arms, each arm having an upper end and a lower end, said arms being coupled to one another for rotational movement about one another at their upper zones, each of said arms having a front surface and a back surface, a first and second set of LEDs at the lower zone of said front face of said first arm, a mounting clip on the front face of said second arm, first and second arms having a storage state in which said back surfaces of said arms are substantially coplanar with one another, said clip carrying second arm having a longitudinal axis, upper and lower portions of said clip carrying second arm being rotatable relative to one another about said longitudinal axis, said upper portion being substantially less than said lower portion, deployment of said first LED carrying arm to a position where illuminating material to be read requiring rotation of said first arm about said first axis and followed by rotation of said first arm and said upper portion of said second arm about said longitudinal second axis, rotation on said first arm about said first axis and rotation of said first arm and upper segment of said second arm above said longitudinal second axis permitting the user to clip said device onto a book cover and to select the incident angle of illumination for the page being read.
 10. The illumination device of claim 9 wherein said first color is in a blue/white range and said second color is in a yellow/white range.
 11. The illumination device of claim 9 wherein: said switch has a third on position to turn on both of said first and second sets of LEDs.
 12. The illumination device of claim 10 wherein: said switch has a third on position to turn on both of said first and second sets of LEDs.
 13. The illumination device of claim 9 wherein said second arm containing said LEDs comprises: first and second longitudinal wings, each of said wings being rotatable at a proximal end about first and second axes respectively, said first and second axes being parallel to each other, one member of said first set of LEDs being positioned near the distal end of each of said subsidiary arms, and one member of each of said second set of LEDs being positioned near the distal end of each of said subsidiary arms, rotation of said wings about said axes providing a larger illuminated area than when said wings are in a retracted position. 